Innovative solution based on the use of two ceramic heaters in selected DEFRO boilers fired with a pellet. Correctly configured controller algorithm adjusts operation ensuring that they operate alternately. It means that only one heater is used for each firing up the process and it is used every second cycle. Use of the TSS system lengthens the time of service of the firing system two times. Furthermore, if one of the heaters is damaged then the second takes its function, what allows trouble-free start-up of the boiler. At the same time, the user is informed about the immediate replacement of the damaged component.